Heavy-duty trucks can be configured to include a “sleeper” compartment attached to the main cab in order to provide long-haul truck operators with a sleeping space inside the truck. For the comfort of the operator while using the sleeper, providing a flow of fresh air to the sleeper is essential. However, the state of the art with regard to sleeper ventilation is presently inadequate.
The traditional means for providing air to the sleeper of a truck is through a cab HVAC system. With reference to FIGS. 4, 5A, and 5B, a typical truck HVAC system 410 will be described. FIG. 4 schematically illustrates a typical HVAC system 410. FIGS. 5A and 5B illustrate side and plan views, respectively, of a typical sleeper truck equipped with an HVAC system 410 similar to that described in FIG. 4.
Air enters the HVAC system 410 via an inlet 414. The air then travels to a fan 418, which feeds accelerated air into an HVAC unit 422 that is configured to heat and/or cool the air provided by the fan 418, or other air moving component. Finally, the “conditioned” air is moved, still by the pressure from the fan 418, from the HVAC unit 422 through cab vents 426 and into the cab 430 of the truck 400.
In FIGS. 5A and 5B, air flow is generally illustrated using dashed arrows, including the flow of conditioned air from the cab vents 426 and the air flow between the cab 430 and sleeper 434. Diffusion is typically relied on for transmitting the conditioned air from the cab 430 to the sleeper 434. However, a typical truck HVAC system 410, such as those illustrated in FIGS. 4-5B, does not provide sufficient fresh air flow to a cab sleeper 434, when in a no-idle state, so as to make the sleeper 434 comfortable for an occupant. While some air may reach the sleeper 434 through diffusion with air in the cab 436, such conditioned air is not fresh air, because it has been heated or cooled.
Conditioned air and fresh air are distinct, as described herein As used herein, the term “treated” air or “conditioned” air means any air that has been heated or cooled intentionally prior to introduction of the air into a truck cab or sleeper. “Fresh air” is referred to herein as air that has not been conditioned prior to introduction into a cab or a sleeper. In current trucks, the amount of fresh air reaching the sleeper is insufficient. It will be appreciated that users of sleeper-equipped trucks attain superior comfort when fresh air is provided instead of, or in addition to, conditioned air.
The most common form of sleeper ventilation is through openable windows or through the use of vents (e.g., Salem vents), which are adjustable openings between the sleeper interior and the vehicle exterior and positioned at oppositely disposed sides of the sleeper. Such vents can provide ample fresh air when the vehicle is in motion, or when the vehicle is at rest and parked at such a position where a cross-breeze flows laterally through the sleeper between the oppositely disposed Salem vents on either side of the sleeper. Because a sleeper is typically only used when the vehicle is parked, reliance on Salem vents for ventilation depends on the unpredictable elements of both an external breeze and the ability to park the truck in a position that adequately captures the breeze.
One solution to the sleeper ventilation problems encountered when using Salem vents is to provide a separate no-idle HVAC system for the sleeper. A typical no-idle cab HVAC system is not adequately configured to provide sufficient fresh air flow to the sleeper; therefore a separate HVAC system for the sleeper can be utilized. However, the additional power (and cost) budget for a second HVAC system can be prohibitive.
Another solution for providing conditioned air to a sleeper is the use of an add-on fan, similar to a desktop fan, mounted in between the sleeper and cab such that conditioned air from the cab (e.g., from the cab-HVAC system) is circulated into the sleeper. Such a solution can be used instead of, or in addition to, Salem vents. However, add-on fans have been found to be ineffective in providing significant air flow and are an added cost and noise source.